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Lysophospholipid transporter LplT and acyltransferase Aas consist of a lysophospholipid-remodeling system ubiquitously found in gram-negative microorganisms. LplT flips lysophospholipid across the inner membrane which is subsequently acylated by Aas on the cytoplasmic membrane surface. Our previous study showed that the proper functioning of this system is important to protecting Escherichia coli from phospholipase-mediated host attack by maintaining the integrity of the bacterial cell envelope. However, the working mechanism of this system is still unclear. Herein, we report that LplT and Aas form a membrane protein complex in E. coli which allows these two enzymes to cooperate efficiently to move lysophospholipids across the bacterial membrane and catalyze their acylation. The direct interaction of LplT and Aas was demonstrated both in vivo and in vitro with a binding affinity of 2.3 µM. We found that a cytoplasmic loop of LplT adjacent to the exit of the substrate translocation pathway plays an important role in maintaining its interaction with Aas. Aas contains an acyl-acyl carrier protein synthase domain and an acyl-transferase domain. Its interaction with LplT is mediated exclusively by its transferase domain. Mutations within the three loops near the putative catalytic site of the transferase domain, respectively, disrupt its interaction with LplT and lysophospholipid acylation activity. These results support a hypothesis of the functional coupling mechanism, in which LplT directly interacts with the transferase domain of Aas for specific substrate membrane migration, providing synchronization of substrate translocation and biosynthetic events.
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BACKGROUND: Lysophosphatidylethanolamines (lyso-PEs) are the partial hydrolysis products of phosphatidylethanolamine. Although lyso-PEs are important biomarkers in various diseases, their determination is limited by the lack of simple and efficient quantification methods. This study aims to develop an improved quantitative method for the determination of lyso-PEs and its application to an epidemiological study. METHODS: Single reaction monitoring channels by collision-induced dissociation for seven lyso-PEs were established using liquid chromatography-tandem mass spectrometry. Plasma lyso-PEs were extracted with a single-phase method using an isotopically labelled internal standard for quantification. The proposed method was adopted to define lyso-PEs in plasma samples of children aged 9-12 years living in Sapporo, Japan. RESULTS: The limit of detection and limit of quantification for each lyso-PE ranged between 0.001-0.015 and 0.002-0.031 pmol/µL, respectively. Recoveries were found to be > 91% for all the species. The analysis results of children's plasma showed that the total lyso-PE concentrations in boys (n = 181) and girls (n = 161) were 11.53 and 11.00 pmol/µL (median), respectively. Participants were further classified by the percentage of overweight and subgrouped as underweight (n = 12), normal range (n = 292), or overweight (n = 38). Interestingly, the reduction of lyso-PE 16:0 and increased lyso-PE 22:6 were observed in overweight children compared with normal range (Fold change: 0.909 and 1.174, respectively). CONCLUSIONS: This study successfully established a simple quantitative method to determine lyso-PE concentrations. Furthermore, our method revealed the possible relation between plasma lyso-PEs and overweight status.
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Glycerophospholipids, a primary component of cellular membranes, play important structural and functional roles in cells. In the remodelling pathway (Lands' cycle), the concerted actions of phospholipase As and lysophospholipid acyltransferases (LPLATs) contribute to the incorporation of diverse fatty acids in glycerophospholipids in an asymmetric manner, which differ between cell types. In this study, the role of LPLATs in osteoblastic differentiation of C2C12 cells was investigated. Gene and protein expression levels of lysophosphatidylcholine acyltransferase 2 (LPCAT2), one of the LPLATs, increased during osteoblastic differentiation in C2C12 cells. LPCAT2 knockdown in C2C12 cells downregulated the expression of osteoblastic differentiation markers and the number and size of lipid droplets (LDs) and suppressed the phosphorylation of Smad1/5/9. In addition, LPCAT2 knockdown inhibited Snail1 and the downstream target of Runx2 and vitamin D receptor (VDR). These results suggest that LPCAT2 modulates osteoblastic differentiation in C2C12 cells through the bone morphogenetic protein (BMP)/Smad signalling pathway.
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This review delves into the enzymatic processes governing the initial stages of glycerophospholipid (phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine) and triacylglycerol synthesis. The key enzymes under scrutiny include GPAT and AGPAT. Additionally, as most AGPATs exhibit LPLAT activity, enzymes participating in the Lands cycle with similar functions are also covered. The review begins by discussing the properties of these enzymes, emphasizing their specificity in enzymatic reactions, notably the incorporation of polyunsaturated fatty acids (PUFAs) such as arachidonic acid and docosahexaenoic acid (DHA) into phospholipids. The paper sheds light on the intricate involvement of these enzymes in various diseases, including obesity, insulin resistance, and cancer. To underscore the relevance of these enzymes in cancer processes, a bioinformatics analysis was conducted. The expression levels of the described enzymes were correlated with the overall survival of patients across 33 different types of cancer using the GEPIA portal. This review further explores the potential therapeutic implications of inhibiting these enzymes in the treatment of metabolic diseases and cancer. By elucidating the intricate enzymatic pathways involved in lipid synthesis and their impact on various pathological conditions, this paper contributes to a comprehensive understanding of these processes and their potential as therapeutic targets.
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Astaxanthin (AST), functioning as an efficient antioxidant and pigment, is one of the most expensive additives in shrimp feeds. How to improve the uptake efficiency of dietary astaxanthin into farmed shrimp is of significance. The present study investigated the effects of lysophosphatidylcholine (LPC), an emulsifier, on dietary astaxanthin efficiency, growth performance, body color, body composition, as well as lipid metabolism of juvenile Pacific white shrimp (average initial body weight: 2.4 g). Three diets were prepared: control group, the AST group (supplemented with 0.02% AST), and the AST + LPC group (supplemented with 0.02% AST and 0.1% LPC). Each diet was fed to triplicate tanks, and each tank was stocked with 30 shrimp. The shrimp were fed four times daily for eight weeks. The AST supplementation improved the growth of white shrimp, while LPC further promoted the final weight of shrimp, but the whole-shrimp proximate composition and fatty acid composition were only slightly affected by AST and LPC. The LPC supplementation significantly increased the astaxanthin deposition in the muscle. The LPC supplementation significantly increased the shell yellowness of both raw and cooked shrimp compared to the AST group. Moreover, the dietary LPC increased the high-density lipoprotein-cholesterol content but decreased the low-density lipoprotein-cholesterol content in the serum, indicating the possible regulation of lipid and cholesterol transport. The addition of astaxanthin significantly up-regulated the expression of npc2 in the hepatopancreas compared to the control group, while the addition of LPC down-regulated the expression of mttp compared to the AST group. In conclusion, the LPC supplementation could facilitate the deposition of dietary astaxanthin into farmed shrimp and further enlarge the beneficial effects of dietary astaxanthin. LPC may also independently regulate shrimp body color and cholesterol transportation. This was the first investigation of the promoting effects of LPC on dietary astaxanthin efficiency.
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Adaptation to hypoxia has attracted much public interest because of its clinical significance. However, hypoxic adaptation in the body is complicated and difficult to fully explore. To explore previously unknown conserved mechanisms and key proteins involved in hypoxic adaptation in different species, we first used a yeast model for mechanistic screening. Further multi-omics analyses in multiple species including yeast, zebrafish and mice revealed that glycerophospholipid metabolism was significantly involved in hypoxic adaptation with up-regulation of lysophospholipid acyltransferase (ALE1) in yeast, a key protein for the formation of dipalmitoyl phosphatidylcholine [DPPC (16:0/16:0)], which is a saturated phosphatidylcholine. Importantly, a mammalian homolog of ALE1, lysophosphatidylcholine acyltransferase 1 (LPCAT1), enhanced DPPC levels at the cell membrane and exhibited the same protective effect in mammalian cells under hypoxic conditions. DPPC supplementation effectively attenuated growth restriction, maintained cell membrane integrity and increased the expression of epidermal growth factor receptor under hypoxic conditions, but unsaturated phosphatidylcholine did not. In agreement with these findings, DPPC treatment could also repair hypoxic injury of intestinal mucosa in mice. Taken together, ALE1/LPCAT1-mediated DPPC formation, a key pathway of glycerophospholipid metabolism, is crucial for cell viability under hypoxic conditions. Moreover, we found that ALE1 was also involved in glycolysis to maintain sufficient survival conditions for yeast. The present study offers a novel approach to understanding lipid metabolism under hypoxia and provides new insights into treating hypoxia-related diseases.
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1-Acilglicerofosfocolina O-Aciltransferasa , Membrana Celular , Glicerofosfolípidos , Animales , Humanos , Ratones , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , 1,2-Dipalmitoilfosfatidilcolina/química , 1-Acilglicerofosfocolina O-Aciltransferasa/metabolismo , 1-Acilglicerofosfocolina O-Aciltransferasa/genética , Adaptación Fisiológica/genética , Membrana Celular/metabolismo , Glicerofosfolípidos/metabolismo , Hipoxia/metabolismo , Hipoxia/genética , Mucosa Intestinal/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crecimiento & desarrollo , Pez Cebra/metabolismo , Pez Cebra/genéticaRESUMEN
Lysophosphatidic acid (LPA), a well-studied member of the lysophospholipid family, is known to exert an important bio-effect on oocyte maturation and ovulation in mammals. We attempted to determine how follicle maturation in the rat ovary affects the levels of LPA and its precursor lysophospholipids, as well as mRNA levels of LPA-producing and -degrading enzymes and LPA receptors in rats that received gonadotropin-hyper-stimulation. Tissue levels of lysophospholipids were quantified by LC-MS/MS, and relative mRNA expression levels of LPA-producing and -degrading enzymes, and LPA receptors were measured by RT-PCR. Tissue levels of n-6 polyunsaturated LPAs and LPCs were higher in the ovaries of rats after receiving human chorionic gonadotropin, unlike the distinct profiles of n-3 polyunsaturated LPAs, which had lower levels, and LPCs which had higher levels, after the gonadotropin treatment. The effects of different levels of other polyunsaturated lysophospholipids were variable: decreased levels of lysophosphatidylglycerol, and unaltered levels of lysophosphatidylethanolamine, lysophosphatidylinositol, and lysophosphatidylserine. The results indicate that expression of mRNA levels of autotaxin and acylglycerol kinase were reduced and expression of lipid phosphate phosphatase 3 was elevated, whereas expressions of two membrane phosphatidic acid phosphatases (A1α and A1ß) and lipid phosphate phosphatase 1 were essentially unaltered in rat ovary at several stages after ovary hyperstimulation. After the gonadotropin treatment, the expression levels of all LPA receptors except LPA3 were decreased at various times. These results are discussed with respect to the physiological processes of the ovarian environment and development in rats.
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Receptores del Ácido Lisofosfatídico , Espectrometría de Masas en Tándem , Femenino , Ratas , Humanos , Animales , Receptores del Ácido Lisofosfatídico/genética , Receptores del Ácido Lisofosfatídico/metabolismo , Cromatografía Liquida , Lisofosfolípidos/metabolismo , Gonadotropinas , ARN Mensajero , Mamíferos/genética , Mamíferos/metabolismoRESUMEN
The gold-standard diagnostic test for peroxisomal disorders (PDs) is plasma concentration analysis of very long-chain fatty acids (VLCFAs). However, this method's time-consuming nature and limitations in cases which present normal VLCFA levels necessitates alternative approaches. The analysis of C26:0-lysophosphatydylcholine (C26:0-LPC) in dried blood spot samples by tandem-mass spectrometry (MS/MS) has successfully been implemented in certain newborn screening programs to diagnose X-linked adrenoleukodystrophy (ALD). However, the diagnostic potential of very long-chain LPCs concentrations in plasma remains poorly understood. This study sought to evaluate the diagnostic performance of C26:0-LPC and other very long-chain LPCs, comparing them to VLCFA analysis in plasma. The study, which included 330 individuals affected by a peroxisomal ß-oxidation deficiency and 407 control individuals, revealed that C26:0- and C24:0-LPC concentrations demonstrated the highest diagnostic accuracy (98.8% and 98.4%, respectively), outperforming VLCFA when C26:0/C22:0 and C24:0/C22:0 ratios were combined (98.1%). Combining C24:0- and C26:0-LPC gave the highest sensitivity (99.7%), with ALD females exhibiting notably higher sensitivity compared with the VLCFA ratio combination (98.7% vs. 93.5%, respectively). In contrast, C22:0-LPC exhibited suboptimal performance, primarily due to its low sensitivity (75%), but we identified a potential use to help distinguish between ALD and Zellweger spectrum disorders. In summary, MS/MS analysis of plasma C24:0- and C26:0-LPC concentrations represents a rapid and straightforward approach to diagnose PDs, demonstrating superior diagnostic accuracy, particularly in ALD females, compared with conventional VLCFA biomarkers. We strongly recommend integrating very-long chain LPC plasma analysis in the diagnostic evaluation of individuals suspected of having a PD.
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Adrenoleucodistrofia , Lisofosfatidilcolinas , Recién Nacido , Femenino , Humanos , Espectrometría de Masas en Tándem , Adrenoleucodistrofia/diagnóstico , Tamizaje Neonatal/métodos , Biomarcadores , Ácidos Grasos no Esterificados , Ácidos GrasosRESUMEN
Cigarette smoking is known to be the leading cause of chronic obstructive pulmonary disease (COPD). However, the detailed mechanisms have not been elucidated. PAF (platelet-activating factor), a potent inflammatory mediator, is involved in the pathogenesis of various respiratory diseases such as bronchial asthma and COPD. We focused on LPLAT9 (lysophospholipid acyltransferase 9), a biosynthetic enzyme of PAF, in the pathogenesis of COPD. LPLAT9 gene expression was observed in excised COPD lungs and single-cell RNA sequencing data of alveolar macrophages (AMs). LPLAT9 was predominant and upregulated in AMs, particularly monocyte-derived AMs, in patients with COPD. To identify the function of LPLAT9/PAF in AMs in the pathogenesis of COPD, we exposed systemic LPLAT9-knockout (LPALT9-/-) mice to cigarette smoke (CS). CS increased the number of AMs, especially the monocyte-derived fraction, which secreted MMP12 (matrix metalloprotease 12). Also, CS augmented LPLAT9 phosphorylation/activation on macrophages and, subsequently, PAF synthesis in the lung. The LPLAT9-/- mouse lung showed reduced PAF production after CS exposure. Intratracheal PAF administration accumulated AMs by increasing MCP1 (monocyte chemoattractant protein-1). After CS exposure, AM accumulation and subsequent pulmonary emphysema, a primary pathologic change of COPD, were reduced in LPALT9-/- mice compared with LPLAT9+/+ mice. Notably, these phenotypes were again worsened by LPLAT9+/+ bone marrow transplantation in LPALT9-/- mice. Thus, CS-induced LPLAT9 activation in monocyte-derived AMs aggravated pulmonary emphysema via PAF-induced further accumulation of AMs. These results suggest that PAF synthesized by LPLAT9 has an important role in the pathogenesis of COPD.
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1-Acilglicerofosfocolina O-Aciltransferasa , Macrófagos Alveolares , Ratones Noqueados , Factor de Activación Plaquetaria , Enfermedad Pulmonar Obstructiva Crónica , Enfisema Pulmonar , Animales , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patología , Humanos , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/patología , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/patología , Enfisema Pulmonar/genética , Factor de Activación Plaquetaria/metabolismo , 1-Acilglicerofosfocolina O-Aciltransferasa/metabolismo , 1-Acilglicerofosfocolina O-Aciltransferasa/genética , Ratones , Masculino , Ratones Endogámicos C57BL , Metaloproteinasa 12 de la Matriz/metabolismo , Metaloproteinasa 12 de la Matriz/genética , Pulmón/metabolismo , Pulmón/patología , Fumar Cigarrillos/efectos adversos , Fumar Cigarrillos/metabolismo , FemeninoRESUMEN
The human malaria parasite Plasmodium falciparum requires exogenous fatty acids to support its growth during the pathogenic, asexual erythrocytic stage. Host serum lysophosphatidylcholine (LPC) is a significant fatty acid source, yet the metabolic processes responsible for the liberation of free fatty acids from exogenous LPC are unknown. Using an assay for LPC hydrolysis in P. falciparum-infected erythrocytes, we have identified small-molecule inhibitors of key in situ lysophospholipase activities. Competitive activity-based profiling and generation of a panel of single-to-quadruple knockout parasite lines revealed that two enzymes of the serine hydrolase superfamily, termed exported lipase (XL) 2 and exported lipase homolog (XLH) 4, constitute the dominant lysophospholipase activities in parasite-infected erythrocytes. The parasite ensures efficient exogenous LPC hydrolysis by directing these two enzymes to distinct locations: XL2 is exported to the erythrocyte, while XLH4 is retained within the parasite. While XL2 and XLH4 were individually dispensable with little effect on LPC hydrolysis in situ, loss of both enzymes resulted in a strong reduction in fatty acid scavenging from LPC, hyperproduction of phosphatidylcholine, and an enhanced sensitivity to LPC toxicity. Notably, growth of XL/XLH-deficient parasites was severely impaired when cultured in media containing LPC as the sole exogenous fatty acid source. Furthermore, when XL2 and XLH4 activities were ablated by genetic or pharmacologic means, parasites were unable to proliferate in human serum, a physiologically relevant fatty acid source, revealing the essentiality of LPC hydrolysis in the host environment and its potential as a target for anti-malarial therapy.
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Malaria Falciparum , Parásitos , Animales , Humanos , Plasmodium falciparum , Lisofosfatidilcolinas/metabolismo , Lisofosfolipasa/genética , Lisofosfolipasa/metabolismo , Malaria Falciparum/parasitología , Eritrocitos/metabolismo , Parásitos/metabolismo , Ácidos Grasos/metabolismo , Lipasa/metabolismo , Proteínas Protozoarias/metabolismoRESUMEN
Postprandial hyperglycemia is an early indicator of impaired glucose tolerance that leads to type 2 diabetes mellitus (T2DM). Alterations in the fatty acid composition of phospholipids have been implicated in diseases such as T2DM and nonalcoholic fatty liver disease. Lysophospholipid acyltransferase 10 (LPLAT10, also called LPCAT4 and LPEAT2) plays a role in remodeling fatty acyl chains of phospholipids; however, its relationship with metabolic diseases has not been fully elucidated. LPLAT10 expression is low in the liver, the main organ that regulates metabolism, under normal conditions. Here, we investigated whether overexpression of LPLAT10 in the liver leads to improved glucose metabolism. For overexpression, we generated an LPLAT10-expressing adenovirus (Ad) vector (Ad-LPLAT10) using an improved Ad vector. Postprandial hyperglycemia was suppressed by the induction of glucose-stimulated insulin secretion in Ad-LPLAT10-treated mice compared with that in control Ad vector-treated mice. Hepatic and serum levels of phosphatidylcholine 40:7, containing C18:1 and C22:6, were increased in Ad-LPLAT10-treated mice. Serum from Ad-LPLAT10-treated mice showed increased glucose-stimulated insulin secretion in mouse insulinoma MIN6 cells. These results indicate that changes in hepatic phosphatidylcholine species due to liver-specific LPLAT10 overexpression affect the pancreas and increase glucose-stimulated insulin secretion. Our findings highlight LPLAT10 as a potential novel therapeutic target for T2DM.
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1-Acilglicerofosfocolina O-Aciltransferasa , Diabetes Mellitus Tipo 2 , Intolerancia a la Glucosa , Animales , Ratones , 1-Acilglicerofosfocolina O-Aciltransferasa/genética , Glucosa/farmacología , Secreción de Insulina , Hígado , Fosfatidilcolinas , FosfolípidosRESUMEN
Acetaminophen (APAP) is a double-edged sword, mainly depending on the dosage. A moderate dose of APAP is effective for fever and pain relief; however, an overdose induces acute liver injury. The mechanism underlying APAP-induced acute liver failure is unclear, and its treatment is limited. A recent report has shown that several oxidized phospholipids are associated with APAP-induced acute liver failure. Lysophosphatidylcholine acyltransferase 3 (Lpcat3, Lplat12), which is highly expressed in the liver, preferentially catalyzes the incorporation of arachidonate into lysophospholipids (PLs). In the present study, we investigated the roles of Lpcat3 on APAP-induced acute liver injury using liver-specific Lpcat3-knockout mice. Hepatic Lpcat3 deficiency reduced the degree of APAP-induced necrosis of hepatocytes around Zone 3 and ameliorated the elevation of hepatic injury serum marker levels, and prolonged survival. Lipidomic analysis showed that the accumulation of oxidized and hydroperoxidized phospholipids was suppressed in Lpcat3-knockout mice. The amelioration of APAP-induced acute liver injury was due not only to the reduction in the lipid synthesis of arachidonic acid PLs because of Lpcat3 deficiency, but also to the promotion of the APAP detoxification pathway by facilitating the conjugation of glutathione and N-acetyl-p-benzoquinone imine. Our findings suggest that Lpcat3 is a potential therapeutic target for treating APAP-induced acute liver injury.
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Acetaminofén , Fallo Hepático Agudo , Animales , Ratones , Acetaminofén/toxicidad , Hepatocitos , Ratones Noqueados , 1-Acilglicerofosfocolina O-AciltransferasaRESUMEN
BACKGROUND: The digestibility of animal fats and oils is limited by a reduction in the production and secretion of lipase and bile salts in young chickens. The addition of a natural emulsifier (lysophospholipids [LPL]) in poultry diet may increase the emulsification of lipids and their digestibility. OBJECTIVES: An experiment was conducted to evaluate the effects of feed LPLs supplementation with different fat sources on performance, serum lipid composition, small intestine morphology and caeca microflora in broiler chickens. METHODS: A completely randomized factorial design (2 × 3 × 2) was used to evaluate the effect of LPL supplementation (0 and 0.25 g/kg) and three different fat sources (soybean oil, tallow and a 50:50 mixture of the two) in corn and soybean meal diets containing two levels of fat (1.5 and 3%), providing 12 isocaloric and isonitrogenous grower diets. Each experimental diet was fed to six replications of 10 birds from 15 to 28 days of age. Average growth performance during this period and small intestine morphology, serum lipid composition and caeca microflora were evaluated on day 28. RESULTS: The interaction effects of LPL supplementation, source and/or level of fats were not significant for the performance parameters measured during the 15 to 28 days. The treatment effects were significant for the villus width and crypt depth measured in the jejunum on day 28. The LPL supplementation significantly increased crypt depth. The interaction effect of fat source and level of fat were significant for villus width. The addition of a 3% blend of soybean oil/tallow (50/50) reduced the serum low-density lipoprotein (LDL) level. The Lactobacillus population was increased by the addition of LPL, or a 1.5% blend of soybean oil and tallow, to the diet. CONCLUSIONS: Our study showed that LPL supplementation of diet containing a 1.5% blend of soybean oil and tallow can improve serum lipid indices and caeca Lactobacillus populations in broiler chickens.
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Suplementos Dietéticos , Aceite de Soja , Animales , Pollos , Intestino Delgado , LisofosfolípidosRESUMEN
The present study aimed to investigate the effect of emulsifier lysophospholipids (LP), enzymatically modified from soy phospholipids, on the growth performance, nutrient digestibility, lipid metabolism and meat quality of fattening rabbits. The LP was added in control (CON), LP1, LP2 and LP3 at 0, 200, 400 and 600 mg/kg, respectively. A total of 240 rabbits at approximately 52 d of age were divided into 4 groups with 6 replicates of 10 rabbits each. The feeding trial lasted for 42 d. Results showed that compared to CON, LP1, LP2 and LP3 increased (p < 0.05) body weight gain, feed efficiency, the apparent faecal digestibility of gross energy, crude protein and ether extract, the percentages of dissectible fat and ether extract in the longissimus and legs, the serum contents of apolipoprotein B, free fatty acid and total phospholipids in the longissimus, but decreased (p < 0.05) serum total triglyceride and total cholesterol. Meanwhile, LP1, LP2 and LP3 had higher (p < 0.05) carcass weight, longissimus weight and percentages of foreleg and hindleg than the CON; and the three LP diets also increased (p < 0.05) the tenderness, lightness and redness of longissimus. It is concluded that soy LP as an emulsifier can improve the growth, digestibility and meat quality of fattening rabbits.
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Dieta , Metabolismo de los Lípidos , Conejos , Animales , Dieta/veterinaria , Digestión , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Nutrientes , Lisofosfolípidos/farmacología , Carne/análisis , Éteres/farmacologíaRESUMEN
Vitamin B12 (B12) deficiency causes neurological manifestations resembling multiple sclerosis (MS); however, a molecular explanation for the similarity is unknown. FTY720 (fingolimod) is a sphingosine 1-phosphate (S1P) receptor modulator and sphingosine analog approved for MS therapy that can functionally antagonize S1P1. Here, we report that FTY720 suppresses neuroinflammation by functionally and physically regulating the B12 pathways. Genetic and pharmacological S1P1 inhibition upregulates a transcobalamin 2 (TCN2)-B12 receptor, CD320, in immediate-early astrocytes (ieAstrocytes; a c-Fos-activated astrocyte subset that tracks with experimental autoimmune encephalomyelitis [EAE] severity). CD320 is also reduced in MS plaques. Deficiency of CD320 or dietary B12 restriction worsens EAE and eliminates FTY720's efficacy while concomitantly downregulating type I interferon signaling. TCN2 functions as a chaperone for FTY720 and sphingosine, whose complex induces astrocytic CD320 internalization, suggesting a delivery mechanism of FTY720/sphingosine via the TCN2-CD320 pathway. Taken together, the B12-TCN2-CD320 pathway is essential for the mechanism of action of FTY720.
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Encefalomielitis Autoinmune Experimental , Esclerosis Múltiple , Animales , Clorhidrato de Fingolimod/farmacología , Clorhidrato de Fingolimod/uso terapéutico , Clorhidrato de Fingolimod/metabolismo , Astrocitos/metabolismo , Esfingosina/metabolismo , Vitamina B 12/farmacología , Vitamina B 12/uso terapéutico , Vitamina B 12/metabolismo , Transcobalaminas/metabolismo , Transcobalaminas/uso terapéutico , Glicoles de Propileno/metabolismo , Glicoles de Propileno/farmacología , Glicoles de Propileno/uso terapéutico , Vitaminas , Inmunosupresores/farmacología , Receptores de Lisoesfingolípidos/metabolismoRESUMEN
Osteoarthritis (OA), a chronic degenerative joint disease, is the most common form of arthritis. OA occurs when the protective cartilage that cushions the ends of bones gradually breaks down. This leads to the rubbing of bones against each other, resulting in pain and stiffness. Cyclic phosphatidic acid (cPA) shows promise as a treatment for OA. In this article, we review the most recent findings regarding the biological functions of cPA signaling in mammalian systems, specifically in relation to OA. cPA is a naturally occurring phospholipid mediator with unique cyclic phosphate rings at the sn-2 and sn-3 positions in the glycerol backbone. cPA promotes various responses, including cell proliferation, migration, and survival. cPA possesses physiological activities that are distinct from those elicited by lysophosphatidic acid; however, its biochemical origin has rarely been studied. Although there is currently no cure for OA, advances in medical research may lead to new therapies or strategies in the future, and cPA has potential therapeutic applications.
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Lysophospholipid acyltransferases (LPLATs), in concert with glycerol-3-phosphate acyltransferases (GPATs) and phospholipase A1/2s, orchestrate the compositional diversity of the fatty chains in membrane phospholipids. Fourteen LPLAT enzymes which come from two distinct families, AGPAT and MBOAT, have been identified, and in this mini-review we provide an overview of their roles in de novo and remodeling pathways of membrane phospholipid biosynthesis. Recently new nomenclature for LPLATs has been introduced (LPLATx, where x is a number 1-14), and we also give an overview of key biological functions that have been discovered for LPLAT1-14, revealed primarily through studies of LPLAT-gene-deficient mice as well as by linkages to various human diseases.
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1-Acilglicerofosfocolina O-Aciltransferasa , Fosfolípidos , Humanos , Animales , Ratones , 1-Acilglicerofosfocolina O-Aciltransferasa/genética , 1-Acilglicerofosfocolina O-Aciltransferasa/metabolismo , Fosfolípidos/metabolismo , Lisofosfolípidos , Aciltransferasas/metabolismoRESUMEN
This study builds on our previous study, which highlighted the need for further research on the potential use of lysophospholipid (LPL) supplementation to prevent chronic and age-related diseases. We aimed to evaluate the transmembrane transport of LPL across rat and monkey blood-brain barrier (BBB) models. An in vitro monkey BBB model is required to elucidate the differences between rat and primate BBB-related data and to measure the permeability of LPLs being researched in relation to the human BBB. Based on our previous experiment, porcine liver decomposition product-derived phospholipids (PEL) strongly inhibit α-synuclein (α-Syn) aggregation. We have identified several candidates potentially relevant for the inhibition of α-Syn aggregation, such as LPC18:1, LPE18:1, and LPI18:0; however, the BBB permeability of these LPLs remains unclear. In the present study, we assessed the ability of these LPLs to pass through the in vitro rat and monkey BBB models. LPC18:1 showed high BBB permeability, LPI18:0 showed medium permeability, and the BBB permeation of LPE18:1 was negligible. Our results suggest that LPC18:1 and LPI18:0 are functional food factors that can cross the BBB.
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GPR82 is an orphan G protein-coupled receptor (GPCR) that has been implicated in lipid storage in mouse adipocytes. However, the intracellular signaling as well as the specific ligands of GPR82 remain unknown. GPR82 is closely related to GPR34, a GPCR for the bioactive lipid molecule lysophosphatidylserine. In this study, we screened a lipid library using GPR82-transfected cells to search for ligands that act on GPR82. By measuring cyclic adenosine monophosphate levels, we found that GPR82 is an apparently constitutively active GPCR that leads to Gi protein activation. In addition, edelfosine (1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine), an artificial lysophospholipid with a cationic head group that exerts antitumor activity, inhibited the Gi protein activation by GPR82. Two endogenous lysophospholipids with cationic head groups, lysophosphatidylcholine (1-oleoyl-sn-glycero-3-phosphocholine) and lysophosphatidylethanolamine (1-oleoyl-sn-glycero-3-phosphoethanolamine), also exhibited GPR82 inhibitory activity, albeit weaker than edelfosine. Förster resonance energy transfer imaging analysis consistently demonstrated that Gi protein-coupled GPR82 has an apparent constitutive activity that is edelfosine-sensitive. Consistent data were obtained from GPR82-mediated binding analysis of guanosine-5'-O-(3-thiotriphosphate) to cell membranes. Furthermore, in GPR82-transfected cells, edelfosine inhibited insulin-induced extracellular signal-regulated kinase activation, like compounds that function as inverse agonists at other GPCRs. Therefore, edelfosine is likely to act as an inverse agonist of GPR82. Finally, GPR82 expression inhibited adipocyte lipolysis, which was abrogated by edelfosine. Our findings suggested that the cationic lysophospholipids edelfosine, lysophosphatidylcholine and lysophosphatidylethanolamine are novel inverse agonists for Gi-coupled GPR82, which is apparently constitutively active, and has the potential to exert lipolytic effects through GPR82.
Asunto(s)
Agonismo Inverso de Drogas , Lisofosfatidilcolinas , Animales , Ratones , Ligandos , Fosforilcolina , Lisofosfolípidos/farmacología , Lisofosfolípidos/metabolismoRESUMEN
Synovial fluid (SF) from human knee joints with osteoarthritis (OA) has elevated levels of lysophosphatidylcholine (LPC) species, but their functional role is not well understood. This in vitro study was designed to test the hypothesis that various LPCs found elevated in OA SF and their metabolites, lysophosphatidic acids (LPAs), modulate the abundance of proteins and phospholipids (PLs) in human fibroblast-like synoviocytes (FLSs), with even minute chemical variations in lysophospholipids determining the extent of regulation. Cultured FLSs (n = 5-7) were treated with one of the LPC species, LPA species, IL-1ß, or a vehicle. Tandem mass tag peptide labeling coupled with LC-MS/MS/MS was performed to quantify proteins. The expression of mRNA from regulated proteins was analyzed using RT-PCR. PL synthesis was determined via ESI-MS/MS, and the release of radiolabeled PLs was determined by means of liquid scintillation counting. In total, 3960 proteins were quantified using multiplexed MS, of which 119, 8, and 3 were significantly and reproducibly regulated by IL-1ß, LPC 16:0, and LPC 18:0, respectively. LPC 16:0 significantly inhibited the release of PLs and the synthesis of phosphatidylcholine, LPC, and sphingomyelin. Neither LPC metabolite-LPA 16:0 nor LPA 18:0-had any reproducible effect on the levels of each protein. In conclusion, small chemical variations in LPC species can result in the significantly altered expression and secretion of proteins and PLs from FLSs. IL-1ß influenced all proteins that were reproducibly regulated by LPC 16:0. LPC species are likely to modulate FLS protein expression only in more advanced OA stages with low IL-1ß levels. None of the eight proteins being significantly regulated by LPC 16:0 have been previously reported in OA. However, our in vitro findings show that the CD81 antigen, calumenin, and B4E2C1 are promising candidates for further study, focusing in particular on their potential ability to modulate inflammatory and catabolic mechanisms.